Optical instrument illumination device



Oct. 24, 1950Y ci. w. wALLHAUsEN E 2,527,043

OPTICAL INSTRUMENT ILLUMINATION DEVICE Original Filed May 4, 1946 2 sheets-sheet 1 au; aman* INVENTOR C HRENCE I4( WAL l H/ql/JE/V ATTORN EYS 0.t 24, 1950 c. w. w-ALLHAUsEN 2,527,043

oPTIcAL INSTRUMENT ILLUMINATION DEVICE original Filed May 4, 1946 2 sheets-sheet 2 ATTORNEYS patented ct. 24, 9-5

UN ES; PAT,lF-,f-jlli'l-` 0 F F l CE f .2,527,043 v i oP'rIcAL INSTRUMENT ILLUM'INATI'ON i DEVICE y 1 `l'Glarerice ,Wallhausen, Morristown,` N. J., als# signor vto United- States Radium Corporation', New a corporation' of Delaware original application-May 4, 1946, serial No., 667,436, now PatentNo. 2,476,340, dated July 19, 1949. Dividediand this Y .1949, serial No, 81,883.

' down; inademen to' the optical muriera andspeaufy eine @here In brief, the Vinvention comprises a device for illuminating the reticle of an optical instrument comprising a band .of thin,f`transliicent material proportioned to nt thelperiphery'of a reticle, "a layer of non-radioactive phosphor disposedfon said material in such positionW that light ema# nating from said phosphoris transmitted through and beyond said material, "and means for support.-

v ing a radioactivefsubst'ance in activating juxtaposition Awith said phosphor.

his applicationvis a division of Lmy copending application for U.K S. Letters Patent ;Serial No.

667,436, filed Mayui, 1946,'grantedJulyu 19, 1949,

as Patent No. 2,476,340. l

Many types' of A optical instruments such as telescopes, range linders, transits and periscopea include a reticle (or reticule) which may'comprise. for example, a glass disc having two plane surfaces, on one of which are engraved cross hairs or calibration marks. usingjth'e instrument, it is necessaryto see themarks or indicia A(here-`V under widely (differing,

inafter called cross hair M 4 1 tance,: :,1.A range nder or light conditions. i For a periscope forr mode n use must ,befemployed in brilliant daylil'glitfwhen subject Lto considerable reflection from the JvIaQi'ei, at V'nightin substantially total darkness, and' in all degreesofintr.- mediate light conditions. Under some" of these conditions `thecross vhairs areV satisfactorily visible without artificial rillumination,but under', other conditions, notably during' twilight, Athev cross hairs are very'difficult` or 'impossible to see."

'To alleviate these disadvantagealfour princi-jj pal proposals have beeninade.' First, 'thereticl'e has been edge-lighted by lsrnall velectric lamps, second, the cross hairs or indicia themselves have comprised either a self-luminouspaint,onthird,v a phosphorescent substance which would glow when activated by an ultrafviolet lamp placed at one side of the reticle, and, fourth, the 'reticle has been edge-lightedby coatingthe peripheral suryface thereof with self-luminous paint.'

application April 16,

reliable electric power. The second and fourth .proposalsjwhich comprise the use of a selfluminous paint, are in some respects an improvement overthe first and third proposals, but these arrangements provide a continuous nonadjustable 'illumination Vespecially. troublesome under twilight conditions" which require a close adjust# ment of the degreev 'ofV illumination to afford `satisffactory operation. However, the more serious ldisadvantage results from the fact that selfluminous paints, which comprise a phosphor activated with a radioactive material intermixed therewith, must be caused tc glow at a high intensity in order to provide sunlcient light.

its' useful life is very short. In most cases such life would not be more than one month, and in many cases not more than two weeks, after which fia new reticle with a fresh 'coating must be subi` stituted in the instrument, orthe old reticle removed and a new coating applied to it. Neither of these practices is feasible in connection with i marine or other remote uses, because, in the first r-"case the spare reticles would' deteriorate at `the;y

same rate as those in use, and the second case calls Afor laboratorytechniques which are.' 'not ordinarily availableat sea or other remote lo-` In accordance with the present invention, 'a luminescent but non-radioactive phosphor is ap`v plied to a thin, translucent, plastic band, strip, "or ring, whichl may readily be applied to, or fittedaroundthe peripheryfof orotherwise to thereti'- "3 cle so as to permit of easy replacement. The ra" dioactive materialis, as described in my men# ticned patent, not admixed with the phosphor;v

but comprises a-separa'te element having an area whichis positioned closely adjacent that lo f the' phosphor, so that 'the radiations from this `material may impinge 'on and' activate the phosphor. i

vlfreferably,'the' radioactive material is arranged to be movable with respect to the phosphor coating on' the reticle so that the respective r areas may be adjusted to overlap completely giving maximum illumination, or so as not to over# lap at all giving zero illumination, or so as to overlap to any desired intermediate degree to provide a corresponding adjustment of the intensity of illumination. Thus the active life of the phosphor is greatly increased because the phosphor deteriorates only during actual use,

viz., whilebeing subjected to bombardment by activating.` radiations...

IA better understanding of the invention may` I diicult requirement forl To' :achieve this high degree of luminosity the phosphor must be activated at such a high rate that line 3-3 of Fig. l, looking inthe direction of the* arrows, the illuminating members'V being in the` positions providing minimum illumination Fig. 4 is a cross-sectionaLview similar'` to that of Fig. 3, but differing therefrom in.` that the il.-

luminating 'members are shown in the positions.:

providing maximum illumination;

Fig. 5 illustrates an eye-piece, generally'similar to that of Fig. l, but in which the adjustable features comprise an alternative embodiment;,

Fig. 6 is a vertical'crossJsectional" view taken" along, the line 6`G'of Fig. 5', looking in the direction of the arrows; and

Fig. '7 is a fragmentary view corresponding to a portion of Fig. 5, but with the movable elements adjusted to provide minimum illumination.whereas Fig. 5 illustrates the same elements in position to provide maximum illumination.

Figs. l, 2 and S'show an eye-piece tube I in which a glass reticl'e 2' isconcentrically mounted by a gripping ring 6l This ring is held in place on the inside of the tube-I'bya threaded inner retaining ring 4' against which the spring ring 6 is pressed by a threaded outer retaining ring 5. The reticle Zcarries cross hairs 3, or additional indicia marks 3a (Fig. 2) which it is desired to illuminate. The nature ofthe indicia may diier in different instruments..

Around the periphery of reticle Zis fitted va thin band or ring 9a ofV translucent" material; such as a suitable plastic, which is coated on the exterior surface with a non-radioactive luminescent phosphor material 9. The phosphor area or areas should be soV positioned on one surface of the band that light emanatingfrom the phosphor is. transmitted through the material ofthe band and'outv the other sidethereof, wherefrom it may l pass to the reticle. If this band is in the form of a closed ring and the inside diameter thereof is suchas to fit snugly aroundthe4 periphery of the reticleit may be slidon to the same andretained there by normal friction. Alternatively,` the coatingmay be applied to anat or curved open bandof suitable material which may be secured aroundthe periphery-.of or otherwise tothe reti-l cle by any appropriate means, suchas cement.

' .'I'hus, this phosphor-coatedband comprises` a discrete article separable from the reticle and therefore' readily'replaceable. A

Various luminous phosphor materials are suitable for the purposes herein described` and it is usually desirable to select a phosphor which is best adapted to the conditionsunder which the particular instrumentv is'to be-used. Forexample, a phosphor comprising ,zincV sulphide provides a yellowish green light which is desirable under many circumstances because of its high brilliancy, and on the other hand a phosphor comprising cadmium silicate provides-a lessbrilliant and orange light which is sometimes desirable. A phosphor comprising cadmium tungstate provides a pale blue light. Suitable mixtures of these or other phosphore are` sometimes; useful. The area or areas of phosphor should be applied in a thin coating so that the luminous particles thereof will not be masked by other particles. It will now be apparent that the present invention permits of several such coated strips or: rings-,being kept; on hand= so 'that the desired one may be'selected and employed under any given conditions.

From the discussion above it will be recalled that the radioactive material is, in accordance "with my Ymentioned invention, mounted separately from the phosphor, in order (1) to increase the life of the phosphor by subjecting it to acjtivating `radiations only when illumination is required,` and (2) toprovide adjustablity of the intensity of illumination, Hence, a suitable radioactive material I0 is afhxed to a rotating ring having. aninner section 8 and an outer section l,

the radioactive material being suitably secured -totheinner section 8. The inner and outer sections are fastened together at three equi-distant points where the inner ring carries a post portion I 5 which" extends ithrough" a' suitable` slot' in` the tube I: three corresponding slots I6 in the tubeA I- are-required;

As'shcvvn` more clearlyinFigs. 2, 3iand 4i the' periphery of the` reticle 2 carriesthree lphosphorl areas "9 equidistantlysp aced' vtherearound'` by lnoncoatedj areas; Threeoorresponding areas of ra dioactiveA material I 0" are Yprovidedl on the -inside surface of the innerring'sectionV 8i Of course,-

as many` coacting areas as desiredmay beA em-4 l' ployed; When the ringl'; 8is turned so that the areas 9 and I0 do notoverla-p'; as shown in Figs. 2 and 3,- substantially' no activatingl radiations from radioactive' surfaces Iii-will impi-ngeupon the surfaces` ofl the'l phosphor-areas 9iy withl the: result that the phosphor-areas 9`-will not glow and hence`theiractive lifewill be^ maintained indefinitely. On the'otherhand, when the'ring is turnedto theright(in"Fig: 3, inthe direction of the arrowlabeled I1luminate)- the areasA 9 and I0 willbe'causedi to'overlap progressively' until they-overlap completely vas'showninA Fig. 4.

Inthis manner theA intensity of 'illumination can be'advjustedfrom substantially zero-to maximum; The mechanism*shouldpreferably be constructedV to provide very?` close spacing between theA areas Sand- Illwhen'in the position of Fig. 4.-

`Although in? accordancel wit-hthe invention any radioactive -rnateriar suitable to activate ai desired phosphor may be'employed for the pur-y pose, I apreferftoiutilize" radioactiveH foil of the types' described in'Ui S."PatentA No; 2,326,631 to Fischen'and in U.S. Letters Patent No. 2,479,882 granted August 23, l949.to me jointly'with.Harry1 H; Dooley and' Clayton' CL' Carroll. The useful life of 'such radioactive foil is longerthan the expected"life`of the instrumental.

The rotatingring 12,8 may be arrangedas above described for manualmovement. in either direc'- tion,V there beingi suicient friction between the ring; members 'I and 8fan'd' the vtube Ito hold'the ringinany desired.l position. However, in some types of opticalinstruments `it is expedient to attach one ormoresprings tothe rotating ring. so

that when the ringis manually movedtowardthe position shown in FiglA-itwill, when released, be automatically returned Y by theaction o f the springs to the position shown inFig. 3. For. this.

purpose twosprings II. (Figs. land- 2) maybe tube I.

There' being'threei such* post' portions,

ally rotated thesspringflisfstretched;; Upon manual. releaseofthe ringusection ,'I, the springs a'iltjofatically'v rotate thMring'lto" the-,posi shown in Fig. 3. .e ,l f

closed in` Figs. 5, 6 and 7.,plfl2ides substaritially?l the ,sewers- 2111@ as. Phase. Yl9iei1-1fi `if1f ri1ythe bodiment above described, but employs adiiferent mechanical.. arrangemen present embodiment the ompojerits orf Qiwn in Figsn Lll,

the embodiment first described.

In Fig. the reticle |02 carries a coating |09 of phosphor applied to a band I09a of translucent material, as before described. In this case, how|h ever, it is feasible to employ a continuous band of phosphor I 09 around the periphery of the reticle by applying the phosphor in a continuous area around the surfaces of the translucent' band I09a, as shown more clearly in Fig. 6.

Instead of being supported on a rotating ring the radioactive material I0 is in this embodiment supported on a tubular sliding sleeve I2. This area of radioactive material may be in the form of a continuousband corresponding to that of phosphor |09. A rack I3 fitted tosleeve I2 coacts with pinion I4 so that when pinion I4 is turned in one direction or the other the sleeve I2 will slide Within the eye-piece tube IUI. As shown in Fig. 5, one extreme position of sleeve I2 results in a substantially complete overlapping of areas |09 and |I0, whereas when the sleeve I2 is moved to the other extreme position,

as shown in Fig. 7, the areas |09 and I|0 do not overlap at all. By this means the illumination of the reticle canbe adjusted from maximum to substantially zero illumination, and likewise permits adjustment to all intermediate degrees of intensity of illumination. ATwo advantages of the embodiment of Figs. 5-7 are that it permits a greater area of glowing phosphor to be used on a given area of the edge of a reticle and, therefore, a greater degree of illumination is possible, and that the illumination is evenly distributed overthe entire area of the edge of the reticle. However, it has been found that for most purposes the degree of illumination and the degree of its uniformity provided by the embodiment iirst de-l scribed are sufficient.

Instead of moving the area of radioactive material by sliding sleeve I2 (Fig. 6) that material may be afhxed to the inner surface of tube IOI, so as to overlap or overlie the phosphor area. Then, if the end of sleeve I2 is shaped to slide between the two areas, in one extreme position it will completely screen the activating radiations from the phosphor surface, and in the other extreme position will not screen any of the radiations. Intermediate positions will provide any other desired change in the amount of radiations which impinge on the phosphor surface.

I claim:

l. A device for illuminating the reticle of an optical instrument, comprising a circular band of thin translucentmaterial, a coating of nonradioactive phosphor on an exterior area of said material such that light emanating from said phosphor is transmitted inwardly through said material, said'band having an inside diameter such as to t snugly around the periphery of a reticle and' to be adapted to be secured to and remavedfromsaid reticleL and means for supia porting-.a radioactive nonfluminous substancey in activating; juxtaposition with said coating.

i2. lA device for illuminating the reticle of vanA optical instrument, comprising a strip of translucent material, a'V coating of non-radioactive` phosphor onqan area of said, material, said strip being of width and lengthk suitable to be secured, tothe periphery of a reticle, and means for supe porting a radioactive non-luminous substance .in

activating. `iuxtaposition with said coating.

p 3.- A device for illuminating `the reticlelof Lan-` optical instrument ,comprising a band vof' thin,- translucent material proportioned to tthe pe-` ripheryl of a reticle, -a coating of non-radioactivev phosphor afixed on.: one surface of said materiali` in suchgposition that light-,emanating from said"l phosphor is transmitted through and 1 beyond said material, and means for supporting a radioactive non-luminous substance in activating juxtaposition with said coating.

`4. A device for illuminating the reticle of an optical instrument comprising a band of thin,

vtranslucent material vproportioned to nt the pe- 5. A device for illuminating the reticle of an` optical instrument comprising a continuous band` of thin, translucent material proportioned to ilt the periphery of a reticle, a plurality of coated areas of non-radio-active phosphor affixed on said band, said areas being spaced apart by noncoated areas along said band in such positions that light emanating from each of said phosphor areas is transmitted through and beyond said material, and means for supporting a radioactive non-luminous substance in activating juxtaposition with said coating.

6. A device for illuminating the reticle of an optical instrument comprising a circular band of thin, translucent material proportioned to fit the periphery of a reticle and having an outer surface and an inner surface, a plurality of coated areas of non-radio-active phosphor afiixed on theV outer surface of said band, said areas being spaced apart by non-coated areas around said band, such that light emanating from each of said phosphor areas is transmitted inwardly through said material and outthrough the inner surface thereof, and means for supporting a radio-active non-luminous substance in activating juxtaposition with said coating.

7. A device for illuminating the reticle of an optical instrument comprising a band of thin,-

translucent material proportioned to t the periphery of a reticle, a plurality of coated areas Y of non-radio-active phosphor aillxed on said band substantially on one side thereof, said areas being spaced apart by non-coated areas along said band and being so positioned that light emanating from each of said phosphor areas is transmitted inwardly through said material and outwardly from the other side thereof, and means for supporting a radio-active non-luminous substance in activating juxtaposition with said coating. f

8. A device for illuminating the reticle of an optical instrument comprising afband of thin, translucent material proportioned to fit the pei'pher'y'- ofV fa mteleg: alayer of flxixi-lifdioctive' phosphor disposed ori-:Sad material iin-"such ipo'si-L tion that vlight emanatingirc'amI said.:phosphor .is transmittedr through and bey'on'd said? materiel, andme ans for supportingf aaradioactive :substance f in- `activating *juxtapositionuwithtfsaid" pifiosphor-f 9. device 4forilluminating Ltheireticle :of iani optical instrument comprising afcontinuos bnrd of lthn, .translucent material proportioned to tf the periphery lof areticle, la plurality-zoffdscrete. areas of. non-radioactive phosphor disposed-'fon said Lband, said L areas being `spaced `apart .along said' balnd Vin such positions that-lightiemanating: fromeacho said phosphor areas is Strstnsnriittedv through vand'beyond sadrmateriahand: rneansLforV supporting a..radioactive substance dnaetvating. juxtaposition .with eechnof. said phosphor areas;

ff CLARENCE. W. WALLHAUSEN.

.- 'following references are 'of vrecordy yin 'the leff'thispatentr' l UNITED-STATES PA'I'ENTS Numier 

